Data communication over a power line

ABSTRACT

Data signals are communicated between a power line and a computer, wherein the power line provides power to the computer via a distribution transformer and the computer is in communication with a wireless communication path. A first data signal is communicated with the power line. A conversion is made between the first data signal and a second data signal capable of being communicated wirelessly. The second data signal is wirelessly communicated with the wireless communication path.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/075,708, entitled “Data Communication over a Power Line”, filed Feb.14, 2002, now U.S. Pat. No. 6,933,835 which claims priority under 35U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No.60/268,519 and of U.S. Provisional Patent Application Ser. No.60/268,578, both filed Feb. 14, 2001.

FIELD OF THE INVENTION

The invention generally relates to data communication over power linesand more particularly, to devices and methods for communicating datasignals with the power lines.

BACKGROUND OF THE INVENTION

A well-established power distribution system exists throughout most ofthe United States and other countries. The power distribution systemprovides power to customers via power lines. With some modification, theinfrastructure of the existing power distribution system can be used toprovide data communication in addition to power delivery. That is, datasignals can be carried by the existing power lines that already havebeen run to many homes and offices. The use of the existing power linesmay help reduce the cost of implementing a data communication system. Toimplement the data communication system, data signals are communicatedto and from the power line at various points in the power distributionsystem, such as, for example, near homes, offices, Internet serviceproviders, and like.

While the concept may sound simple, there are many challenges toovercome before using power lines for data communication. For example, asufficient signal-to-noise ratio should be maintained, a sufficient datatransfer rate should be maintained (e.g., 10 Mbps), “add on” devicesshould be installable without significantly disrupting power supply topower customers, “add on” devices should be designed to withstandoutdoor conditions, bi-directional data communication should besupported, data communication system customers should be protected fromthe voltages present on power lines, and the like.

Power system transformers are one obstacle to using power distributionlines for data communication. Transformers convert voltages betweenpower distribution system portions. For example, a power distributionsystem may include a high voltage portion, a medium voltage portion, anda low voltage portion and a transformers converts the voltages betweenthese portions. Transformers, however, act as a low-pass filter, passinglow frequency signals (e.g., 50 or 60 Hz power signals) and impedinghigh frequency signals (e.g., frequencies typically used for datacommunication) from passing through the transformer. As such, a datacommunication system using power lines for data transmission faces achallenge in passing the data signals from the power lines a to customerpremise.

Moreover, accessing data signals on a power lines is a potential safetyconcern. Medium voltage power lines can operate from about 1000 V toabout 100 kV which can generate high current flows. As such, anyelectrical coupling to a medium voltage power line is a concern.Therefore, a need exists for a device that can safely communicate datasignals with a medium voltage power line and yet provide electricalisolation from the medium voltage power line.

In addition to communicating a data signal with a medium voltage powerline, it would be advantageous to communicate the data signal to acustomer premise. That is, a need also exists for a device thatelectrically communicates a data signal between a medium voltage powerline and a low voltage power line, while maintaining electricalisolation between the medium voltage power line and the low voltagepower line.

SUMMARY OF THE INVENTION

The invention is directed to communicating data signals with a powerline and wirelessly communicating the data signals to a computer,wherein the power line feeds power to the computer via a distributiontransformer. A first data signal is communicated with the power line,wherein the first data signal is an analog data signal capable of beingcarried by the power line. A conversion is made between the first datasignal and a second data signal capable of being transmitted wirelesslyto the computer. The second data signal is wirelessly communicated withthe computer.

The first data signal may be inductively communicated with the powerline. The converting may comprise modulating and demodulating the firstdata signal with Orthogonal Frequency Division Multiplexing and routingthe first data signal. The converting may further comprise convertingthe first data signal to a radio frequency signal, to a microwavefrequency signal, to a signal formatted in compliance with an IEEE802.11 protocol, to a light data signal and then to a wireless datasignal, and to an acoustic frequency signal.

The first data signal may be received from the power line and convertedto a data signal capable of being transmitted wirelessly to the computerand then be transmitted to the computer. The second data signal may bewirelessly received from the computer, converted to an analog datasignal capable of being carried by the power line and communicated tothe power line.

A system for communicating data between a power line and a computerincludes a coupling device, a signal converter, and a wirelesstransceiver. The coupling device couples to the power line andcommunicates a first data signal with the power line. The signalconverter communicates with the coupling device and converts between thefirst data signal and a second data signal capable of being transmittedwirelessly to the computer. The wireless transceiver wirelesslycommunicates the second data signal with the computer.

The coupling device may comprise an inductor. The signal converter maycomprise a modem, a data router, an optoelectronic transceiver, a radiofrequency transceiver, a microwave frequency transceiver, an antenna,and an acoustic transceiver.

The above-listed features, as well as other features, of the inventionwill be more fully set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described in the detailed description thatfollows, by reference to the noted drawings by way of non-limitingillustrative embodiments of the invention, in which like referencenumerals represent similar parts throughout the drawings. As should beunderstood, however, the invention is not limited to the precisearrangements and instrumentalities shown. In the drawings:

FIG. 1 is a diagram of an exemplary power distribution system with whichthe invention may be employed;

FIG. 2 is a diagram of the exemplary power distribution system of FIG. 1modified to operate as a data communication system, in accordance withan embodiment of the invention;

FIG. 3 is a block diagram of a portion of a data communication system,in accordance with an embodiment of the invention;

FIG. 4 is a block diagram of a portion of a data communication system,in accordance with an embodiment of the invention;

FIG. 5 is a perspective view of a power line coupler and a power linebridge installed at a telephone pole of a power distribution system, inaccordance with an embodiment of the invention;

FIG. 6 is a schematic of a power line coupler, in accordance with anembodiment of the invention;

FIG. 7 is a schematic of another power line coupler, in accordance withanother embodiment of the invention;

FIG. 8 is a diagram of another portion of a data communication system,in accordance with another embodiment of the invention; and

FIG. 9 is a flow diagram of an illustrative method for datacommunication over a power line, in accordance with an embodiment of theinvention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

A power line coupler and a power line bridge communicate data signalsacross a transformer that would otherwise filter the data signals frompassing through the transformer. Further, the power line couplerprovides high electrical isolation between the transformer primary sideand secondary side, thereby preventing substantial power flow throughthe power line coupler and the power line bridge. It should beappreciated that the functionality of the power line coupler and thepower line bridge can be included in one device or distributed in morethan one device. The power line coupler may include a power linecoupling device that communicates data signals with a power line,circuitry to condition the data signal, circuitry to handlebi-directional signal transfer, circuitry to enable the use of anelectrical isolator, circuitry to provide operational power from thepower line, and may be designed to be self-contained. The power linecoupler may include circuitry to communicate with the power line couplerand circuitry to convert data signals to a second format forcommunication to a customer premise.

An exemplary power distribution system is shown in FIG. 1. As shown inFIG. 1, power distribution system 100 is a medium voltage half looppower distribution system that is common to the United States. Theinvention, however, may be employed with other power distributionsystems, such as, for example, a high voltage delivery system that iscommon to European countries, as well as other power distributionsystems.

Power distribution system 100 includes components for power generationand power transmission and delivery. As shown in FIG. 1, a powergeneration source 101 is a facility that produces electric power. Powergeneration source 101 includes a generator (not shown) that creates theelectrical power. The generator may be a gas turbine or a steam turbineoperated by burning coal, oil, natural gas, or a nuclear reactor, forexample. Power generation source 101 typically provides three-phase ACpower. The generated AC power typically has a voltage as high asapproximately 25,000 volts.

A transmission substation (not shown) increases the voltage from powergeneration source 101 to high-voltage levels for long distancetransmission on high-voltage transmission lines 102. Typical voltagesfound on high-voltage transmission lines 102 range from 69 to in excessof 800 kilovolts (kV). High-voltage transmission lines 102 are supportedby high-voltage transmission towers 103. High-voltage transmissiontowers 103 are large metal support structures attached to the earth, soas to support the transmission lines and provide a ground potential tosystem 100. High-voltage transmission lines 102 carry the electric powerfrom power generation source 101 to a substation 104.

In addition to high-voltage transmission lines 102, power distributionsystem 100 includes medium voltage power lines 120 and low voltage powerline 113. Medium voltage is typically from about 1000 V to about 100 kVand low voltage is typically from about 100 V to about 240 V. As can beseen, power distribution systems typically have different voltageportions. Transformers are often used to convert between the respectivevoltage portions, e.g., between the high voltage portion and the mediumvoltage portion and between the medium voltage portion and the lowvoltage portion. Transformers have a primary side for connection to afirst voltage and a secondary side for outputting another (usuallylower) voltage. Transformers are often referred to as a step downtransformers because they typically “step down” the voltage to somelower voltage. Transformers, therefore, provide voltage conversion forthe power distribution system. This is convenient for power distributionbut inconvenient for data communication because the transformers candegrade data signals, as described in more detail below.

A substation transformer 107 is located at substation 104. Substation104 acts as a distribution point in system 100 and substationtransformer 107 steps-down voltages to reduced voltage levels.Specifically, substation transformer 107 converts the power onhigh-voltage transmission lines 102 from high voltage levels to mediumvoltage levels for medium voltage power lines 120. In addition,substation 104 may include an electrical bus (not shown) that serves toroute the medium voltage power in multiple directions. Furthermore,substation 104 often includes circuit breakers and switches (not shown)that permit substation 104 to be disconnected from high-voltagetransmission lines 102, when a fault occurs on the lines.

Substation 104 typically is connected to at least one distributiontransformer 105. Distribution transformer 105 may be a pole-toptransformer located on a utility pole, a pad-mounted transformer locatedon the ground, or a transformer located under ground level. Distributiontransformer 105 steps down the voltage to levels required by a customerpremise 106, for example. Power is carried from substation transformer107 to distribution transformer 105 over one or more medium voltagepower lines 120. Power is carried from distribution transformer 105 tocustomer premise 106 via one or more low voltage lines 113. Also,distribution transformer 105 may function to distribute one, two, three,or more phase currents to customer premise 106, depending upon thedemands of the user. In the United States, for example, these localdistribution transformers typically feed anywhere from one to ten homes,depending upon the concentration of the customer premises in aparticular location.

Transformer 105 converts the medium voltage power to low voltage power.Transformer 105 is electrically connected to medium voltage power lines120 on the primary side of the transformer and low voltage power lines113 on the secondary side of the transformer. Transformers act as alow-pass filter, passing low frequency signals (e.g., 50 or 60 Hz powersignals) and impeding high frequency signals (e.g., frequenciestypically used for data communication) from passing from the transformerprimary side to the transformer secondary side. As such, a datacommunication system using power lines 120 for data transmission faces achallenge in passing the data signals from the medium voltage powerlines 120 to customer premises 106.

FIG. 2 illustrates the power distribution system of FIG. 1 as modifiedfor operation as a data communication system, in accordance with anembodiment of the invention. As described above, a power distributionsystem is typically separated into high voltage power lines, mediumvoltage power lines, and low voltage power lines that extend to customerpremises 106. The high voltage power lines typically have the leastamount of noise and least amount of reflections. These high voltagepower lines have the highest potential bandwidth for datacommunications. This is convenient because it is the portion thatconcentrates the bandwidth from the other low and medium voltageportions. The type of signal modulation used on this portion can bealmost any signal modulation used in communications (Code DivisionMultiple Access (CDMA), Time Division Multiple Access (TDMA), FrequencyDivision Multiplex (FDM), Orthogonal Frequency Division Multiplex(OFDM), and the like). Typically, OFDM is used on both the low andmedium voltage portions. A modulation producing a wideband signal suchas CDMA that is relatively flat in the spectral domain may be used toreduce radiated interference to other systems while still deliveringhigh data communication rates.

Medium voltage power lines 120 and low voltage power lines 113 typicallyhave some noise present from electrical appliances and reflections dueto the “web” of wires in those portions. Low power voltage lines 113often have more noise than medium voltage power lines 120. Theseportions of the power distribution system typically support a lowerbandwidth than the high voltage power lines and therefore, usuallyemploy a more intelligent modulation scheme (typically with moreoverhead). There are several companies with commercially available chipsets to perform modulation schemes for local area networks (LANs) suchas, for example: Adaptive Networks (Newton, Mass.), Inari (Draper,Utah), Intellion (Ocala, Fla.), DS2 (Valencia, Spain) and Itran(Beer-Sheva, Israel).

As shown in FIG. 2, a power line coupler 200 communicates with mediumvoltage power line 120 and a power line bridge 210 communicates with lowvoltage power line 113. Further, power line coupler 200 and power linebridge 210 communicate with each other to allow data signals to bypasstransformer 105, as described in more detail below. A power lineinterface device 250 can plug into an electrical outlet and operates toallow customers to access the data signal on the low voltage power line113. An aggregation point 220 operates to allow a service provider toaccess data signals on medium voltage power line 120. It should beappreciated that although power line coupler 200 and power line bridge210 are shown in FIG. 2 as being located at a specific location, thepower line coupler and the power line bridge functionality may belocated in various locations on the power system.

Returning to power line coupler 200 and power line bridge 210, FIG. 3illustrates an example of their operation. As described above, bridgingdata signals between portions of the power distribution system can be aproblem, because of the low pass filtering aspect of a transformer. Toovercome the problem, power line coupler 200 and power line bridge 210form an electrically non-conductive path 300 for communicatingnon-electrically conducting signals around transformer 105, therebybypassing the low-pass filtering of transformer 105. While electricallynon-conductive path 300 does not pass significant amounts of power, itdoes allow data signals to bypass transformer 105. That is, power linecoupler 200 interfaces data signals to medium voltage power lines 120 onthe primary side of transformer 105 and power line bridge 210 interfacesdata signals to low voltage power lines 113 on the secondary side oftransformer 105.

Power line coupler 200 and power line bridge 210 communicate with eachother, thereby allowing data signals to bypass transformer 105, thusavoiding the filtering of the high frequency data signal that otherwisewould occur in transformer 105. Lower frequency power signals continueto flow from medium voltage power lines 120 to low voltage power lines113 via transformer 105. Power line coupler 200 provides electricalisolation between medium voltage power lines 120 and low voltage powerlines 113 by substantially preventing power from flowing overelectrically non-conductive path 300.

FIG. 4, illustrates more detail of power line coupler 200 and power linebridge 210. As shown in FIG. 4, power line coupler 200 includes a powerline coupling device 400 and an electrically non-conductive device 410.

Power line coupling device 400 communicates data signals with mediumvoltage power line 120. Power line coupling device 400 may include, forexample, a current transformer, an inductor, a capacitor, an antenna,and the like.

Electrically non-conductive device 410 provides electrical isolationbetween medium voltage power lines 120 and low voltage power lines 113and communicates non-electrically conducting signals. Electricallynon-conductive device 410 may be a fiber optic cable, a light pipe, asufficiently wide air gap, a sufficiently wide dielectric material, andthe like.

Power line bridge 210 may include a modem 420, a data router 430, amodem 440, an electrically non-conductive device 450, and a power linecoupling device 460.

Modem 420 modulates and demodulates data signals between power linecoupler 200 and data router 430. Modem 420 typically is selected tooptimize the communication of the data signals over medium voltage powerline 120. For example, modem 420 may be selected to operate with a 50MHz carrier frequency. Further, modem 420 may be selected to use amodulation technique, such as, for example, CDMA, TDMA, FDM, OFDM, andthe like.

Router 430 routes digital data signals between modem 420 and modem 440.Router 430 may receive and send data packets, match data packets withspecific messages and destinations, perform traffic control functions,perform usage tracking functions, authorization functions, throughputcontrol functions, and the like.

Modem 440 modulates and demodulates data signals between power linecoupler 460 and data router 430. Modem 440 typically is selected tooptimize the communication of the data signals over low voltage powerline 113. Modem 440 may be selected to operate with a carrier frequencywithin the range of 2 to 24 MHz, for example. Further, modem 420 may beselected to modulate using a technique, such as, for example, CDMA,TDMA, FDM, OFDM, and the like. The use of modems 420 and 440 allows themodulation technique for each modem to be individually matched to thecharacteristics of the power line with which it communicates. Ifhowever, the same modulation technique is used on both low voltage powerlines 113 and medium voltage power lines 120, modem 420, data router430, and modem 440 may be omitted from power line bridge 210.

Electrically non-conductive device 450 provides electrical isolationbetween low voltage power lines 113 and modem 440. Electricallynon-conductive device 450 may be a fiber optic cable, a light pipe, asufficiently wide air gap, a sufficiently wide dielectric material, andthe like. Because low voltage power lines 113 operate at a low voltage,electrically non-conductive device 450 may include a capacitor. That is,a capacitor can provide a sufficient electrical isolation between lowvoltage power lines 113 and a customer. Power line coupling device 460may include a current transformer, an inductor, a capacitor, an antenna,and the like.

FIG. 5 illustrates an installation of power line coupler 200 and powerline bridge 210 to a power distribution system. As shown in FIG. 5,power line coupler 200 is mounted proximate medium voltage power line120 and power line bridge 210 is mounted proximate low voltage powerline 113. Power line coupler 200 and power line bridge 210 are incommunication via communication medium 500. Communication medium 500 maybe a fiber optic cable, an air gap, a dielectric material, and the like.

Power line coupler 200 receives a data signal from medium voltage powerline 120. Power line coupler 100 converts the data signal to anon-electrically conducting signal (i.e., a signal that can betransmitted over a non-electrically conductive path). A non-electricallyconducting signal may be a light signal, a radio frequency signal, amicrowave signal, and the like. Power line coupler 200 transmits thesignal over communication medium 500. Power line bridge 210 receives thenon-electrically conducting signal and conditions the signal forcommunication over low voltage power line 113 to customer premise 106(as discussed with reference to FIG. 2).

Rather than communicating data signals to customer premise 106 via lowvoltage power line 113, power line bridge 210 may use othercommunication media. FIG. 5 depicts several other techniques forcommunicating data signals to customer premise 106. For example, powerline bridge 210 may convert the data signals to electric data signalsand communicate the electric data signals via telephone line 550 orcoaxial cable line 554. Such communication may be implemented in asimilar fashion to the communication with low voltage power line 113.

Power line bridge 210 may convert the data signal to radio signals forcommunication over a wireless communication link 556. In this case,customer premise 106 includes a radio transceiver for communicating withwireless communication link 556. In this manner, power line bridge 210functions as a communication interface, converting the non-electricallyconducting signal to a signal appropriate for communication to customerpremise 106. Wireless communication link 556 may be a wireless localarea network implementing a network protocol in accordance with the IEEE802.11 standard.

Alternatively, light signals may be communicated to customer premise 106directly via a fiber optic 552. In this alternative embodiment, powerline bridge may convert the data signals to light signals forcommunication over fiber optic line 552. Alternatively, the data signalsalready may be in light form and therefore, power line coupler maycommunicate directly with user premise 106. In this embodiment, customerpremise 106 may have a fiber optic connection for carrying data signals,rather than using the internal wiring of customer premise 106.

FIG. 6, illustrates more details of power line coupler 200. As shown inFIG. 6, power line coupler 200 includes an inductor 602, capacitors 606,transmit circuitry 610, receive circuitry 612, transmit optoelectronicdevice 620, and receive optoelectronic device 622.

Inductor 602 communicates data signals with medium voltage power line120 via magnetic coupling. Inductor 602 may be a toroidally shapedinductor that is inductively coupled with medium voltage power line 120.Inductor 602 includes a toroidally shaped magnetic core with windings604 disposed to facilitate flux linkage of the data signal on mediumvoltage power line 120. The number and orientation of windings 604typically is selected for increased flux linkage. Further, thepermeability of the magnetic core typically is selected for highcoupling with the high frequency data signal and a high signal to noiseratio. Also, the permeability characteristics of inductor 602 may beselected to reduce saturation of the core. If the core becomessaturated, the data signal may become “clipped.”

Medium voltage power line 120 may be disposed through inductor 602. Tofacilitate easy installation and minimal impact to customer service,inductor 602 may include a hinge. With such a hinge, inductor 602 maysimply snap around medium voltage power line 120 using existing utilitytools and techniques. In this manner, installation of inductor 602 canbe performed without disrupting power to the power users and withoutstripping any insulation from medium voltage power line 120.

Inductor 602 is electrically connected to capacitors 606. Capacitors 606provide some electrical isolation between optoelectronic devices 620,622 and inductor 602. Capacitors 606 further provide filtering of thepower signal from the data signal. That is, the data signal, whichtypically is a high frequency signal, passes across capacitors 606 whilethe power signal, which typically is a lower frequency (e.g., 50 or 60Hz), is substantially prevented from passing across capacitors 606.While such filtering need not be implemented necessarily, filteringtypically is included to simplify the design of system. Alternatively,such filtering may be implemented elsewhere within system 200, forexample, in transmit circuitry 610, receive circuitry 612, power linebridge 210, and the like.

Capacitors 606 are electrically connected to transmit circuitry 610 andreceive circuitry 612. Transmit circuitry 610 and receive circuitry 612may amplify the data signal, filter the data signal, buffer the datasignal, modulate and demodulate the signal, and the like. Transmitcircuitry 610 typically is selected to maximize the power of the datasignal to keep the signal-to-noise ratio of the data signal at anacceptable level. Receive circuitry 612 typically includes an amplifierdesigned to handle the lowest expected received data signal level. At asystem level, the modulation and demodulation techniques typically areselected to reduce interference between transmit and receive signals.

Transmit circuitry 610 and receive circuitry 612 are electricallyconnected to transmit optoelectronic device 620 and receiveoptoelectronic device 622, respectively. Transmit optoelectronic device620 converts a light data signal, for example, from communication medium630 to an electrical data signal for use by transmit circuitry 610.Transmit optoelectronic device 620 may include a light emitting diode, alaser diode, a vertical cavity surface emitting laser, and the like.Receive optoelectronic device 622 converts an electrical data signalfrom receive circuitry 612 to a light data signal for transmissionthrough communication medium 630. Receive optoelectronic device 622 mayinclude a photosensitive diode, photosensitive transistor, and the like.

Transmit optoelectronic device 620 and receive optoelectronic device 622are in communication with communication medium 630. As shown, lightsignals are communicated between both transmit circuitry 610 and receivecircuitry 612 and communication medium 630.

Communication medium 630 communicates light signals between power linecoupler 100 and the power line bridge 210. Communication medium iselectrically nonconductive, thereby breaking the electrically conductivepower path between power line coupler 200 and power line bridge 210.Communication medium 630 may include a light pipe, a fiber-optic cable,and the like.

In this manner, data signals on the power lines are converted to lightsignals and are transmitted over optical communication medium 630.Similarly, light signals from optical communication medium 630 areconverted to electrical signals for communication with the power lines.Communication medium 630, being electrically non-conductive, providesthe increased safety that is desired by many power distributioncompanies by not allowing substantial power to flow throughcommunication medium 630.

Power line coupler 200 includes a power supply inductor 680 and a powersupply 682. Power supply inductor 680, constructed similar to inductor602, inductively draws power from medium voltage power line 120. Powersupply inductor 680 typically is selected to have magneticcharacteristics appropriate for coupling power signals from mediumvoltage power line 120. Power supply 682 receives power from inductor680 (e.g., alternating current (ac) power) and converts the power to anappropriate form for use by transmit circuitry 610, receive circuitry612, and the like (e.g., direct current (dc) power). As such, power linecoupler 200 can be a “closed” system, internally deriving its own powerand thereby avoiding the use of batteries (which may be costly andimpractical).

Power line coupler 200 includes a housing 650 to protect it fromexposure to the environmental conditions. Housing 650 may be constructedwith high dielectric, corrosive resistant materials, fasteners,adhesives, and sealed conduit openings. Housing 650 may further bedesigned to reduce the risk of exposure to the voltage potential presenton medium voltage power line 120.

In the embodiment illustrated in FIG. 6, communication medium 630 is afiber optic cable that provides electrical isolation between mediumvoltage power line 120 and low voltage power line 113. Othercommunication media may be used to provide such electrical isolation.For example, inductor 602 may include an annularly shaped dielectricmaterial disposed coaxially between medium voltage power line 120 andinductor 602. The dielectric material allows inductor 602 to bemagnetically coupled to medium voltage power line 120, thereby allowingcommunication of data signals. The dielectric material does not allowsignificant power to pass from medium voltage power line 120 to lowvoltage power line 113. Alternatively, rather than converting theelectric data signals to light data signals, power line coupler 200 mayconvert the electric data signals to wireless data signals, such as, forexample, radio frequency signals.

FIG. 7 illustrates another embodiment of a power line coupler 200′. Asshown in FIG. 7, power line coupler 200′ includes a radio frequency (RF)choke 705, capacitors 710, a transformer 720, transmit circuitry 610,receive circuitry 612, transmit optoelectronic device 620, and receiveoptoelectronic device 622.

RF choke 705 may be disposed around and is directly connected to mediumvoltage power line 120 and may comprise ferrite beads. RF choke 705operates as a low pass filter. That is, low frequency signals (e.g., apower signal having a frequency of 50 or 60 Hz) pass through RF choke705 relatively unimpeded (i.e., RF choke 705 can be modeled as a shortcircuit to low frequency signals). High frequency signals (e.g., a datasignal), however, do not pass through RF choke 705; rather, they areabsorbed in RF choke 705 (i.e., RF choke 705 can be modeled as an opencircuit to high frequency signals). As such, the voltage across RF choke705 includes data signals but substantially no power signals. Thisvoltage (i.e., the voltage across RF choke 705) is applied totransformer 720 via capacitors 710 to receive data signals from mediumvoltage power line 120. To transmit data signals to medium voltage powerline 120, a data signal is applied to transformer 720, which in turncommunicates the data signal to RF choke 705 through capacitors 710.

Capacitors 710 provide some electrical isolation between medium voltagepower line 120 and transformer 720. Capacitors 710 further providesfiltering of stray power signals. That is, the data signal passes acrosscapacitors 710 while any power signal is substantially prevented frompassing across capacitors 710. Such filtering can be implementedelsewhere within the system or not implemented at all.

Transformer 720 may operate as a differential transceiver. That is,transformer 720 may operate to repeat data signals received from RFchoke 705 to receive circuitry 612 and to repeat data signals receivedfrom transmit circuitry 610 to RF choke 705. Transformer 720 alsoprovides some electrical isolation between medium voltage power line 120and low voltage power line 113.

Capacitors 606 may be electrically connected between transmit circuitry610 and receive circuitry 612 and transformer 720. Transmit circuitry610 and receive circuitry 612 are electrically connected to transmitoptoelectronic device 620 and receive optoelectronic device 622,respectively. Transmit optoelectronic device 620 and receiveoptoelectronic device 622 are in communication with communication medium630. Power line coupler 200′ may include a power supply inductor 680, apower supply 682, and a housing 650, similar to that shown in FIG. 6.

In the embodiments illustrated in FIGS. 6 and 7, communication medium630 is a fiber optic cable that provides electrical power isolationbetween medium voltage power line 120 and low voltage power line 113.Other communication media may be used to provide such electrical powerisolation. For example, inductor 602 may include an annularly shapeddielectric material (not shown) disposed coaxially within inductor 602.The dielectric material allows inductor 602 to be magnetically coupledto medium voltage power line 120, thereby allowing communication of datasignals. The dielectric material does not allow significant power topass from medium voltage power line 120 to low voltage power line 113.Alternatively, inductor 602 may communicate with a wireless transceiver(not shown) that converts data signals to wireless signals. In thiscase, communication medium 630 is air.

Returning to FIG. 2, power line coupler 200 communicates data signalswith power line bridge 210, that is turn communicates the data signalsto low voltage power line 113. The data signal carried by low voltagepower line 113 is then provided to power line interface device 250 vialow-voltage premise network 130. Power line interface device 250 is incommunication low-voltage premise network 130 and with various premisedevices that are capable of communicating over a data network, such asfor example, a telephone, a computer, and the like.

Power line interface device 250 converts a signal provided by power linebridge 210 to a form appropriate for communication with premise devices.For example, power line interface device 250 may convert an analogsignal to a digital signal for receipt at customer premise 106, andconverts a digital signal to an analog signal for data transmitted bycustomer premise 106.

Power line interface device 250 is located at or near the connection oflow voltage power line 113 with customer premise 106. For example, powerline interface device 250 may be connected to a load side or supply sideof an electrical circuit breaker panel (not shown). Alternatively, powerline interface device 250 may be connected to a load side or supply sideof an electrical meter (not shown). Therefore, it should be appreciatedthat power line interface device 250 may be located inside or outside ofcustomer premise 106.

A “web” of wires distributes power and data signals within customerpremise 130. The customer draws power on demand by plugging an applianceinto a power outlet. In a similar manner, the user may plug power lineinterface device 250 into a power outlet to digitally connect dataappliances to communicate data signals carried by the power wiring.Power line interface device 250 serves as an interface for customer dataappliances (not shown) to access data communication system 200. Powerline interface device 250 can have a variety of interfaces for customerdata appliances. For example, power line interface device 250 caninclude a RJ-11 Plain Old Telephone Service (POTS) connector, an RS-232connector, a USB connector, a 10 Base-T connector, and the like. In thismanner, a customer can connect a variety of data appliances to datacommunication system 200. Further, multiple power line interface devices250 can be plugged into power outlets in the customer premise 130, eachpower line interface device 250 communicating over the same wiring incustomer premise 130.

In alternative embodiments, rather than using low voltage power lines113 to carry the data signals and power line interface device 250 toconvert the data signals, power line bridge 210 converts data signals tobe carried by another medium, such as, for example, a wireless link, atelephone line, a cable line, a fiber optic line, and the like.

As described above a customer can access data communication system 200via power line interface device 250. A service provider, however,typically accesses data communication system 200 via aggregation point220, as shown in FIG. 2. FIG. 8 shows more details of aggregation point220. As shown in FIG. 8, power line coupling device 200 communicatesbetween medium voltage power line 120 and aggregation point 220.Aggregation point 220 includes a modem 810, a backhaul interface 820,and a backhaul link 830 Aggregation point 220 allows a service providerto access data communication system 200.

FIG. 9 is a flow diagram of an illustrative method 900 for communicatingdata between medium voltage power line 120 and low voltage power line113. As shown in FIG. 9 at step 910, a data signal is received frommedium voltage power line 120. Typically, the data signal is in the formof a high-frequency electrical signal. At step 920, the data signal isconverted from an electrical signal to a light signal. At step 930, thelight signal is communicated to a fiber optic cable and at step 940, thelight signal is received. At step 950 the light signal is converted backto an electric data signal and at step 960, the electric data signal iscommunicated to medium voltage power line 120.

The invention is directed to directed to a power line coupler and apower line bridge that communicate data signals across a transformerthat would otherwise filter the data signals from passing through thetransformer. Further, the power line coupler provides high electricalisolation between the transformer primary side and secondary side. Thepower line coupler can be used to provide data services to residencesand service providers. Possible applications include remote utilitymeter reading, Internet Protocol (IP)-based stereo systems, IP-basedvideo delivery systems, and IP telephony, Internet access, telephony,video conferencing, and video delivery, and the like.

It is to be understood that the foregoing illustrative embodiments havebeen provided merely for the purpose of explanation and are in no way tobe construed as limiting of the invention. Words which have been usedherein are words of description and illustration, rather than words oflimitation. Further, although the invention has been described hereinwith reference to particular structure, materials and/or embodiments,the invention is not intended to be limited to the particulars disclosedherein. Rather, the invention extends to all functionally equivalentstructures, methods and uses, such as are within the scope of theappended claims. Those skilled in the art, having the benefit of theteachings of this specification, may affect numerous modificationsthereto and changes may be made without departing from the scope andspirit of the invention.

1. A communication device for communicating over a power distributionsystem comprising a power line carrying a power signal having a voltagegreater than one thousand volts, said power distribution systemsupplying power to a plurality of customer premises via a plurality ofexternal low voltage power lines, comprising: an inductive coupler to becommunicatively coupled to the power line; a modem communicativelycoupled to said coupler and configured to communicate data over thepower line; and a wireless transceiver communicatively coupled to saidmodem and capable of communicating with a plurality of remotetransceivers disposed in one or more of the plurality of customerpremises thereby bypassing the external low voltage power lines.
 2. Thedevice of claim 1, wherein said inductive coupler is comprised of amagnetically permeable material having an aperture through which thepower line may traverse.
 3. The device of 2, wherein said couplercomprises a toroid.
 4. The device of claim 3, wherein said couplercomprises a first portion coupled to a second portion via a hinge. 5.The device of claim 4, further comprising a router in communication withsaid modem.
 6. The device of claim 5, wherein said router monitors usagedata.
 7. The device of claim 1, further comprising an inductive powercoupler configured to inductively couple power from the power signalcarried by the power line.
 8. The device of claim 7, wherein said powercoupler is electrically connected to said modem to provide powerthereto.
 9. The device of claim 8, wherein said power coupler is connectto said modem through an AC-DC converter.
 10. The device of claim 1,further comprising a router in communication with said modem.
 11. Acommunication device for communicating over a power distribution systemcomprising a power line having a voltage greater than one thousandvolts, the power distribution system supplying power to a plurality ofcustomer premises via a plurality of external low voltage power lines,comprising: a data signal impedance coupled to the power line andcomprising a magnetically permeable toroid; a coupler comprising a firstport and a second port wherein said first port is coupled to the powerline on a first side of the data signal impedance and the second port ofsaid coupler is coupled to the power line on the second side of the datasignal impedance; a modem communicatively coupled to said coupler; and awireless transceiver communicatively coupled to said modem and capableof communicating with a plurality of remote transceivers disposed in oneor more of the plurality of customer premises thereby bypassing theexternal low voltage power lines.
 12. The device of claim 11, furthercomprising a router in communication with said modem.
 13. The device ofclaim 12, wherein said router monitors usage data.
 14. A communicationdevice for communicating over a power distribution system comprising apower line having a voltage greater than one thousand volts, the powerdistribution system supplying power to a plurality of customer premisesvia a plurality of external low voltage power lines, comprising: acapacitive coupler communicatively coupled to the power line; a modemcommunicatively coupled to said coupler and configured to communicateover the power line; and a wireless transceiver communicatively coupledto said modem, wherein said wireless transceiver is capable ofcommunicating with a plurality of remote wireless transceivers at theplurality of customer premises thereby bypassing the external lowvoltage power lines.
 15. The device of claim 14, further comprising arouter in communication with said modem.
 16. The device of claim 15,wherein said router monitors usage data.
 17. A method of communicatingdata signals over a power distribution system comprising a power linehaving a voltage greater than one thousand volts, the power distributionsystem supplying power to a plurality of customer premises via aplurality of external low voltage power lines, comprising: at a firstlocation: inductively coupling a first data signal from the power line;demodulating the first data signal to provide first digital data; andwirelessly transmitting a second data signal based on said first digitaldata to a remote transceiver at one of the plurality of customerpremises thereby bypassing the external low voltage power lines.
 18. Themethod of claim 17, further comprising: wirelessly receiving a thirddata signal from the remote transceiver; demodulating the third datasignal to provide second digital data; modulating the second digitaldata to provide a fourth data signal; and inductively coupling thefourth data signal to the power line.
 19. The method of claim 18,further comprising, at a second location: inductively coupling thefourth data signal from the power line; and demodulating the fourth datasignal to provide the second digital data.
 20. A method of communicatingdata signals over a power distribution system comprising a power linehaving a voltage greater than one thousand volts, the power distributionsystem supplying power to a plurality of customer premises via aplurality of external low voltage power lines, comprising: wirelesslyreceiving a first data signal through the air from a remote transceiverlocated at one of the plurality of customer premises thereby bypassingthe external low voltage power lines; demodulating the first data signalto provide first digital data; modulating the first digital data toprovide a second data signal; and inductively coupling the second datasignal to the power line.
 21. A communication device for communicatingover a power distribution system that comprises a power line carrying apower signal having a voltage greater than one thousand volts, the powerdistribution system supplying power to a plurality of customer premisesvia a plurality of external low voltage power lines, comprising: a datacoupler to be communicatively coupled to the power line; a modemcommunicatively coupled to said coupler and configured to communicatevia the power line; a wireless transceiver communicatively coupled tosaid modem and capable of communicating with a plurality of a remotetransceivers at one or more of the plurality of customer premisesthereby bypassing the external low voltage power lines; and a powercoupler configured to inductively couple power from the power signalcarried by the power line, wherein power from said power couplersupplies power to said modem.
 22. The device of claim 21, furthercomprising a router communicatively coupled to said modem.
 23. Thedevice of claim 22, wherein said router monitors usage data.
 24. Thedevice of claim 21, wherein the data coupler is an inductive coupler.25. The device of claim 21, wherein the data coupler is a capacitivecoupler.
 26. The device of claim 21, wherein said power couplercomprises a magnetically permeable material having an aperture throughwhich the power line may traverse.
 27. The device of claim 26, whereinsaid power coupler comprises a toroid.
 28. The device of claim 26,wherein said data coupler comprises a first portion coupled to a secondportion via a hinge.
 29. A method of communicating data signals over apower distribution system comprising a power line having a voltagegreater than one thousand volts, the power distribution system supplyingpower to a plurality of customer premises via a plurality of externallow voltage power lines, comprising: capacitively coupling a first datasignal from the power line; demodulating the first data signal toprovide first digital data; and wirelessly transmitting a second datasignal based on said first digital data to a remote transceiver at oneof the plurality of customer premises thereby bypassing the external lowvoltage power lines.